docs: def rename_file(self, old_path, new_path):
          """Rename a file or directory.
  
          NOTE: This method is unfortunately named on the base class.  It
          actually moves a file or a directory.
          """
          self.log.debug("S3contents.GenericManager: Init rename of '%s' to '%s'", old_path, new_path)
          if self.file_exists(new_path) or self.dir_exists(new_path):
              self.already_exists(new_path)
          elif self.file_exists(old_path) or self.dir_exists(old_path):
              self.log.debug("S3contents.GenericManager: Actually renaming '%s' to '%s'", old_path,
                             new_path)
              self.fs.mv(old_path, new_path)
          else:
              self.no_such_entity(old_path)